1. Field of the Invention
This invention relates to a mixer circuit for use in a converter (frequency converting circuit), a measuring instrument, etc.
2. Related Background Art
Through a recent attempt to rapidly develop information network system, demand for a satellite communication system has been also rapidly increased, and a frequency band has been shifted to high frequency. In this type of satellite communication system, a down converter for converting a high-frequency signal to a low-frequency signal is required, and a mixer circuit which is applied to the down converter has been also increasingly demanded. There have been conventionally utilized various types of mixer circuits, each of which uses any one of a diode, a bipolar transistor, a FET (field effect transistor), etc. as an active device thereof. An normal MESFET (Metal-semiconductor field effect transistor) or a HEMT (high electron mobility transistor) has been generally used.